The tachometer can perform both contact and non-contact measurements. Additionally, it is possible to measure surface speed. The tachometer allows measurements of up to 99,999 revolutions per minute. This measurement range is achievable with non-contact measurements using the optical tachometer. In contact measurements, values of up to 19,999 revolutions per minute can be determined, and the surface speed measurement allows for speeds of up to 1999.9 meters per minute to be assessed. Such measurements can be initiated directly with the tachometer and require minimal preparation. The user does not need to pay attention to the direction of rotation when using the tachometer, as this device operates independently of it. Therefore, it is particularly useful for the maintenance and servicing of machines. The non-contact measurement also enables the checking of rotational speed on hard-to-reach components.